Re: reread doesn't

[<pl...@pi...>]

Le 29.09.2015 18:14, sfeam a écrit :
> On Tuesday, 29 September 2015 12:04:04 PM pl...@pi... wrote:
> 
>> Hi
> 
>> 
> 
>> I am producing a graph ( SVG ) by using load command.
> 
>> 
> 
>> To refresh it periodically, I have a pause and a reread at the end.
> 
> You can only have one plot in an svg output file, "refresh it" is
> 
> not an option. You would have to close it, reopen another file
> 
> with the same name, and write a new plot into it.
> 
> Is that what your script does?
> 
> "reread" only resets the input file, not the output file.
> 
> It is possible you misunderstand where the "reload" command
> 
> needs to go. Is there an "unset output" before it?
> 
>> The problem is the reread does NOT reread the file. I seems to have
> an
> 
>> internal buffer and just pretends to reread.
> 
> Not sure who you mean by "I".


sorry, typo, I meant "it" ie gnuplot as you surmised.


> 
> If you mean gnuplot, then no.
> 
> But if you mean the operating system, then probably yes.
> 
> Gnuplot's "reread" command tells the system to go back to the
> 
> beginning of the file. That is a "rewind" operation, not a
> 
> "close and re-open for reading" operation.
> 
>> I can not find anything that would force an actual reread of the
> file.
> 
>> 
> 
>> It would be extremely useful if it did really reread the file on
> disk
> 
>> since this would allow another process to modify it.
> 
> No, sorry. File systems don't work that way. If somebody else
> 
> writes on top of a file you already have open for reading, that
> 
> is probably not going to do what you seem to expect.
> 
>  > I seem to recall that there was some complication with this same
> 
>> functionality needing to support pipes or direct input.
> 
>> 
> 
>> Is there not a way to force a actual reload of the file? Maybe a '
> 
>> reread really ' option.
> 
>  Ethan


Thanks, reread is basically doing a seek(0), not a close and open which 
I what I was looking for, which is why I was looking for "reread really" 
type solution. Reread does what it says, in fact.

  What I was needing was a 'reload'.  That would indeed require closing 
the output file before using it.


Yes, I do close the svg by unset output;

regard, Peter.